无需重新编码即可剪切mp4 h264视频文件

Question

I am searching for a way to split or cut a mp4 video file encoded with h264, without reencoding. So far for editing a mp4 h264 encoded file I used Microsoft Expression Encoder 4 Pro. The problem is, that I always have to reencode the file and this takes time, unnecessary time if I only want to cut or split the video file. Any help or pointing into the right direction is appreciated.

Answer 1

I do not know how to split video without re-encoding (transcoding) but on Windows 8 transcoding a video has been built-in:

To trim the file, call the aysnc method PrepareFileTranscodeAsync and then call the TranscodeAsync method on the PrepareTranscodeResult object.

For example:

async void TrimFile(StorageFile srcFile, StorageFile destFile)
{
    MediaEncodingProfile profile =
        MediaEncodingProfile.CreateMp4(VideoEncodingQuality.HD720p);

    MediaTranscoder transcoder = new MediaTranscoder();

    // Set the start of the trim.
    transcoder.TrimStartTime = new TimeSpan(0, 0, 1);

    // Set the end of the trim.
    transcoder.TrimStopTime = new TimeSpan(0, 0, 9);

    PrepareTranscodeResult prepareOp = await
        transcoder.PrepareFileTranscodeAsync(srcFile, destFile, profile);

    if (prepareOp.CanTranscode)
    {
        var transcodeOp = prepareOp.TranscodeAsync();
        transcodeOp.Progress +=
            new AsyncActionProgressHandler<double>(TranscodeProgress);
        transcodeOp.Completed +=
            new AsyncActionWithProgressCompletedHandler<double>(TranscodeComplete);
    }
    else
    {
        switch (prepareOp.FailureReason)
        {
            case TranscodeFailureReason.CodecNotFound:
                OutputText("Codec not found.");
                break;
            case TranscodeFailureReason.InvalidProfile:
                OutputText("Invalid profile.");
                break;
            default:
                OutputText("Unknown failure.");
                break;
        }
    }
}

How to trim a video file (Windows Store apps using C#/VB/C++ and XAML)

It is also possible to Splicer (uses DirectShow.Net ) for older Windows.

Hopefully it helps someone.

Answer 2

libmp4v2 gives you the primitives to build something to do this yourself. Im not aware of a free off the shelf solution that does just this, though it would be relatively easy to implement as long as you are cutting on I frame boundaries.